SINCE the publication of the first edition in 1970, the metric (SI) system has become fully established in this country and in many countries overseas as the system of units in use in the civil engineering industry. Amendments have been made in the text to take account of this, and the original chapter relating to the changeover to metric units has been deleted.
A new chapter has been included to deal with the more specialized aspects of house drainage and smaller sewerage schemes, and the opportunity has been taken to correct a few comparatively minor errors of the earlier edition.
Since 1970 there have been considerable changes in the standards of materials used in civil engineering. A number of British Standard Specifications have been withdrawn and new Standards have been issued. New types of pipe materials have come into use and the earlier standards for iron and asbestos-cement pipes have been revised.
Public health engineering (as with all branches of civil engineering) is continually developing, and this continuous process must, of necessity, be reflected in a new edition of a book of this nature. In that respect, the author has made a number of changes to the section devoted to the early preparation of schemes, as there have been many new developments following the re-organisation of local government in the UK.